Uniform temperature cooling system for engines



Se t. 3, 1957 A. A. TACCHELLA ET 2,804,860

UNIFORM TEMPERATURE COOLING SYSTEM FOR ENGINES Filed Sept. 17, 1956 INVENTORS AWUZP/v 4. TAC'C'HEZLA 1 5N010 N. ANDERSON ATTORNEY UNIFORM TEMPERATURE COOLING YSTEM FOR ENGENES Adolph A. Tacchella, Altadena, and Arnold N. Anderson, Manhattan Beach, Calif.

Application September 17, 1956, Serial No. 610,198 9 Claims. (Cl. 123-4121) This invention relates to a cooling system for internal combustion engines and the like, in which a liquid coolant circulates through the engine at or near its boiling point and the cooling of the heated surfaces of the engine takes place largely by ebullition.

Engine cooling by ebullition offers the advantages of a substantially constant cooling temperature after the boiling point of the liquid has been reached, and an extremely low or small differential between the temperatures of the coolant entering and leaving the engine. The advantages of these features on fuel and maintenance economy are well known for stationary installations, and it is an object of this invention to extend these benefits to mobile and semi-mobile engines where their good influence on operating economy will be even more pronounced than in stationary engines.

It is another object of the invention to provide a cooling system of the character referred to that will function in a highly efficient manner at any ambient temperature as may be encountered in commercial and/ or military installations. Hence, the present system may operate successfully on water alone or on water anti-freeze mixtures, as required, and without any change in arrangement of the apparatus involved or any components of such apparatus.

In order that a single cooling system be provided using either water alone or water mixed with anti-freeze liquid, it is necessary to obviate separation of the water and antifreeze in the cooling cycle. Accordingly, another object of the invention is to provide a cooling system that completely separates the engine coolant circulating system and the radiator-cooled circulating system. In other words, the invention contemplates coolant circulation through the engine by thermal action, independent circulation of another and radiator-cooled coolant, and utilization of a heat-exchanging interengagement of said two separate circulations.

Since the present system operates with an engine coolant circulating at or near its boiling point, no intentional cooling of the circulating liquid is or need be provided and the heat rejected to the coolant or absorbed by it is represented by the amount of steam generated in the cooling passages.

A further object of the invention is to provide a cooling system embodying means to establish thermosiphon circulation of coolant in a circuit that is, in part, separate from the circuit established under load and conditions of ebullition.

The invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in a working position and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novel combinations and arrangements of parts, which will more fully appear in the course of the follow ing description. However, the drawing merely shows and the following description merely describes, one embodiment of the present invention, which is given by way of illustration or example only.

In the drawing, like reference characters designate similar parts in the several views.

The figure is a semi-diagrammatic view of a preferred form of the present Cooling system for engines.

The engine 5 that is illustrated is intended as generally typical of an internal combustion engine, the same having the usual coolant inlet tube 6 and outlet tube 7. A conventional radiator 8 is shown in association with said engine, the liquid flowing therethrough being cooled by air circulation induced by mobility of the installation and/or a fan 9, as shown.

The circulation of the engine coolant passes through a at its bottom, with coolant outlet tube 6 and, at its side,

with coolant inlet tube 7. Said housing is provided with a filler opening 13 somewhat below where inlet tube 7 connects and, at the top, with a thermostaticvent 14.

A vertically disposed tube 15 within the housing divides the latter into the respective inner and outer chambers 16 and 17. Said tube 15 is aligned with the tube 6 and extends to a point somewhat above the level of the tube 7. Communication between chambers 16 and 17 is afforded through openings 18 in the lower end of tube 15 and openings 19 in the upper end thereof. Said upper end of the tube 15 is provided with a condensate-catching tray 20 that directs condensate into said tube.

As hereinabove indicated, the vapor separator 10're' heat, thus causing a rise in the temperature of the coolant.

Most of this heat is transferred as latent heat of evaporation and is evidenced by formation of steam bubbles. During the rise through the coolant passages of the mixture of coolant and bubbles, additional bubbles are formed therein. The same is discharged into the separator 10 and the described cycle is repeated.

Since the steam or vapor that is trapped in chamber 21 in the upper portion of housing 12 above Where tube 7 connects must be condensed so that the condensate may be returned to the above-described engine circuit, a condensing circuit 22 is provided, the same including the mentioned radiator 8 and condenser 11.

The condenser 11 may take any desired form so that the circulation therethrough may have a heat exchange relationship with the steam in chamber 21. In this instance, the condenser 11 is shown as two condenser elements 23 disposed above tray 20 so that condensation caused thereby may fall into said tray for re-circulation through the engine 5.

The condensing circuit 22 includes a conduit 24 extending from the lower end of radiator 8 to the elements of the condenser 11, a pump 25 in said conduit to force, flow in the direction of the arrow 26, and a conduit 27 extending from the condenser 11 to the upper end of said radiator.

The conduit 24 may embody a heat exchanger 28 in the form of a cooler for the oil used to lubricate engine 5. Tubes 29 may connect the cooler 28 and the engine, substantially as shown.

A bypass connection 30 between the coolant discharge .1

Patented Sept. 3, 1957- header a of the engine and chamber 17 of the housing 12 is provided, the same allowing flow of coolant from the engine to the separator when the engine is cold. The primary diiference between the flow in tubes 7 and 22 is that the flow in the former comprises both coolant liquid and bubbles of steam, and the flow in the latter comprises coolant liquid only. 7

The circuit 22 includes a thermostatic valve 31 that cuts out the radiator when the coolant circulating in said circuit is closed. A bypass 32, parallel to said radiator, connects conduits 24 and 27 to carry the circulation until valve 11 opens so that the circulation may pass through the radiator.

On starting up, the circulation of the coolant in the engine is by thermosiphon and the coolant will rise in the engine and enter the housing 12 through connection 30 and return through tube 6 to the engine. As the temperature of the coolant increases the liquid level in the housing 12 will first rise because of thermal expansion of the coolant, and, after the boiling point is reached, the rise will continue because of the displacement of coolant in the engine-cooling passages by steam bubbles. The steam or vapor will separate itself from. the coolant in housing 12 and rise into chamber 21, displacing air in said chamber through thermostatic vent valve 14. When steam reaches said valve, the same closes because of its thermal response to the heat of the steam.

The quantity of vapor or steam that is generated varies in relation to the load on the engine. When the engine idles, very little vapor is produced, but the amount thereof increases with increase of load. However, the temper ature of the coolant remains practically constant. If, after the boiling point is reached, the temperatures of the cylinder-walls of the engine stayabove the dew point of the residual gases of combustion, no condensation of these gases nor of raw fuel can take place. Consequently, wear on the cylinder walls is greatly reduced and sludge formation in the engine crankcase largely is eliminated.

Since the present apparatus is required to operate successfully at extremely low ambient temperatures, frequently as low as -65 F., it is important that freezing of the condensate be avoided. To this end, the apparatus provides and locates a condenser in which slushing or freezing of the condensate is completely eliminated.

Thus, the condenser 11 is located in upper chamber 21 of the separator housing 12 and the condensing fluid circulating therethrough is part of a circulating system using radiator 8 to dissipate heat that may be rejected in both the condenser and the oil cooler 28. The ambient temperature conditions will determine whether this circulating liquid shall be water or a mixture of water. and anti-freeze liquid.

In operation, the vapor rising from the liquid level in housing 12 flows upwardly in heat exchangecontact with the units of condenser 11, the same circulating toward the condenser after flowing around the outer edges of tray 20. The resultant condensate drains into said tray and thence into chamber 16 to join the return flow to the engine. During this operation, the liquid in outer chamber 17 is under agitation due to the inflow of the coolant and vapor mixture from the conduit 7, the tube 15 that separates chambers 16 and 17 causing aquiescent down-flow of the condensate that, while otherwise undisturbed, mixes with liquid passing through apertures 18 to provide the mentioned return flow to the engine. The mentioned quiescence is somewhat affected by the small turbulent flow from the lower portion of chamber 21, through apertures 19 into compartment or chamber 16. Thus, the quiescence in chamber 17 is only relative to the turbulence in chamber 17 and good admixing of condensate and antifreeze liquid is achieved.

The condensing liquid is kept from freezing by causing thesame to bypass the radiator 8 under low ambient temperature conditions and to circulate through passage 321instead;

Since most of the heat transfer in the present system is by ebullition, the steam or vapor bubbles that are generated in the cooling passages cause an expansion of volume of the liquid and a consequent rise in level from the level 33 to the level 34.

Because of such rise in the level of liquid in housing 12, tube 7 enters said housing at the high level shown, so that the vapor in the flow may readily separate out and rise in chamber 21. The passage 22 is necessary to enable thermosiphon circulation before the formation of steam bubbles. It will be understood that, as ebullition increases, there is a transition of the flow from the tube 22 to the tube 7. The provision of thermosiphon circulation is not only important for the usual reason that starting and stopping temperature dilierences are reduced, but also because the condensate is mixed more intimately with the coolant which, if the latter is an anti-freeze liquid, is extremely important under low ambient temperatures.

While the foregoing has illustrated and described what is now contemplated to be the best mode of carrying out our invention, the construction is, of course, subject to modification without departing from the spirit and scope of the invention. It is, therefore, not desired to restrict the invention to the particular form of construction illustrated and described, but to cover all modifications that may fall within the scope of the appended claims.

Having thus described our invention, what we claim and desire to secure by Letters Patent is:

l. The combination with an engine having a coolant circulating therethrough and having outlet and inlet circulating conduits for said coolant, of a housing connected to receive coolant from the outlet conduit and including an upper chamber receptive of vapor bubbles released from the coolant entering the housing, the housinghaving a lower. chamber connected to the inlet conduit of the engine and in which the non-vaporized coolant circulates, a condenser disposed in. heat exchanger relationship with the vapor. bubbles in said upper chamber, and means providing an independent circulation of coolant through said condenser to condense said vapor for gravitational deposit into the lower chamber and return to the coolant circulating insaid lower chamber.

2. The combination according to claim 1 in which a condensate-collecting tray is provided beneath the condenser and said tray is disposed to discharge into the central portionot the lower chamber.

3. The combination with an engine having a coolant circulating therethrough and having outlet and inlet circulating conduits for said coolant, of a housing connected to receive coolant from the outlet conduit and including an upper chamber receptive of vapor bubbles released from the coolant entering the housing, the housing having a lower chamber connected to the inlet conduit of the. engine and in which thenon-vaporized coolant circulates, a condenser disposed in heat exchanger relationship with the vapor bubbles in said upper chamber, the lower chamber being divided into an outer part that receives the mentioned circulation of coolant from the engine outlet and an inner part for receiving the condensate from the upper chamber, said chamber parts being in communication adjacent where the engine inlet conduit joins the housing, and means providing an independent circulation of coolant through said condenser to condense said vapor for gravitational deposit into the lower chamber and return to the coolant circulating in said lower chamber.

4. The combination with an engine having a coolant circulating therethrough and having outlet and inlet circulating conduits for said coolant, ofa housing connected to receive coolant from the outlet conduit and including an upper chamber receptive of vapor bubbles released from the coolant entering the housing, the housing havinga lower chamber connected to the inlet conduit of the engine and in which the non-vaporized coolant circulates,

a condenser disposed in heat exchanger relationship with the vapor bubbles in said upper chamber, the lower cham her being divided into an outer part that receives the mentioned circulation of coolant from the engine outlet and an inner part for receiving the condensate from the upper chamber, said chamber parts being in communication adjacent where the engine inlet conduit joins the housing, a condensate-collecting tray beneath the condenser to direct flow of condensate directly into the inner chamber part, and means providing an independent circulation of coolant through said condenser to condense said vapor for gravitational deposit into the lower chamber and return to the coolant circulating in said lower chamber.

5. The combination with an engine having a coolant circulating therethrough and having outlet and inlet circulating conduits for said coolant, of a housing connected to receive coolant from the outlet conduit and including an upper chamber receptive of vapor bubbles released from the coolant entering the housing, the housing having a lower chamber connected to the inlet conduit of the engine and in which the non-vaporized coolant circulates, a condenser disposed in heat exchanger relationship with the vapor bubbles in said upper chamber, means providing an independent circulation of coolant through said condenser to condense said vapor for gravitational deposit into the lower chamber and return to the coolant circulating in said lower chamber, and a radiator embodied in the latter means to absorb heat from the independent circulation of coolant.

6. The combination with an engine having a coolant circulating therethrough and having outlet and inlet circulating conduits for said coolant, of a housing connected to receive coolant from the outlet conduit and including an upper chamber receptive of vapor bubbles released from the coolant entering the housing, the housing having a lower chamber connected to the inlet conduit of the engine and in which the non-vaporized coolant circulates, a condenser disposed in heat exchanger relationship with the vapor bubbles in said upper chamber, means providing an independent circulation of coolant through said condenser to condense said vapor for gravitational deposit into the lower chamber and return to the coolant circulating in said lower chamber, a bypass connection across the radiator and thermostatic means to direct the coolant circulation through said bypass under conditions of low ambient temperatures, and a radiator embodied in the latter means to absorb heat from the independent circulation of coolant.

7. In combination, a first coolant-circulating system including the passages of an engine, a housing, and outlet and inlet connections of coolant between said engine passages and said housing, and a steam separator in the upper portion of said housing above both said connections; and an independent coolant-circulating system including a heat exchanger condenser disposed within the steam separator of said housing of the first circulating system to condense steam released by the coolant of said first system.

8. In combination, a first coolant-circulating system including the passages of an engine, a housing, and outlet and inlet connections of coolant between said engine passages and said housing, and a steam separator in the upper portion of said housing above both said connections; an independent coolant-circulating system including a heat exchanger condenser disposed within the steam separator of said housing of the first circulating system to condense steam released by the coolant of said first system; and means to collect the condensate of the first system and to embody the same in coolant circulating toward the engine in the inlet connection.

9. In combination, a first coolant-circulating system including the passages of an engine, a housing, and outlet and inlet connections of coolant between said engine passages and said housing and a steam separator in the upper portion of said housing above both connections; a second outlet connection from the engine to the housing is provided, the same entering the housing at a level beneath the level of entry of the first-mentioned outlet; an independent coolant-circulating system including a heat exchanger condenser disposed within the steam separator of said housing of the first circulating system to condense steam released by the coolant of said first system; and means to collect the condensate of the first system and to embody the same in coolant circulating toward the engine in the inlet connection.

Fry Sept. 2, 1930 Nallinger Apr. 8, 1941 

